Polyamide textile materials, e.g. nylon carpets, are provided with stain blocking properties by application of coating comprising a sulfonated compound which, because it is not chemically bonded to the fiber, can be removed, with extensive washings. One object of this invention is to provide polyamide textile materials with enhanced stainblocking properties having sulfonate groups chemically attached to the nitrogen in the polymer backbone. Another object of this invention is to provide sulfonated polyamides as thin surface coatings on polyamide substrates or a bulk solutions of sulfonated polyamide for preparing films or coatings. Another object of this invention is to provide sulfonated polyamide coatings with noble metal counterions for use as catalytic surfaces for electroless deposition of metal. These and other objects will be more readily apparent from the following description of the invention and illustrative examples.